A pressurized boiler (1) for a steam generator appliance comprises an evaporation chamber (78), an electric heater (60) in good thermal contact with a wall (70) of the evaporation chamber (78), a water inlet (77) arranged in a cover (72) of the evaporation chamber (78) separate from said wall (70), and a pump in fluid communication with the water inlet (77) arranged to supply water to the evaporation chamber (78) through the water inlet (77).